Almost all major access equipment manufacturers, including Alcatel, Ericsson, Paradyne, UTstarcom, Huawei, Siemens, and others, have made available ADSL2+-compliant DSLAMs and modems, continuously expanding the range of available products and incorporating more sophisticated features (e.g. Annex B for access over ISDN lines or and Annex J/M for symmetric services).
As “triple play” services become commonplace among residential customers, directly competing against traditional media networks (e.g., high-quality video broadcast over terrestrial or satellite), ageing ADSLbased broadband access networks will be upgraded to ADSL2+. However, the adoption of ADSL2+ as the access technology of choice does not immediately enable high-end multimedia-rich services for all.
The measurement-based evaluation of the technology has shown that the performance of ADSL2+ is highly dependant on the loop length, just as all the various flavours of the DSL family. Even the extended-reach feature, specifically developed to counter the adverse effects of increased loop lengths, only offers about 500m of extra coverage. Furthermore, even though HDTV-based services can (marginally) be offered over ADSL2+ broadband access, even more advanced future Super HDTV- and Ultra HDTV-based services can certainly not. The bandwidth needed by the latter two may exceed by a large margin the ADSL2+ limits and indeed the limitations of copper-based broadband access.
In the short term and in view of the limitations of ADSL2+, a new DSL access technology has been developed as an alternative to a full Fibre-to-the-Home access solution, namely the VDSL2 technology. Its short distance reach however requires a supporting Fibre-to-the-Curb network, which, in most countries, is only now beginning to materialise.
